James a



(No Model.)

J. A. CHRISTY.

TELEPHONE. No. 480,656. Patented' Aug. 9, 1892.

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UNITED STATES PATENT OFFICE.

JAMES A. CHRISTY, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THOMAS W. COSGROVE, BERNARD SHRAFL,

FRONA EUNICE WAIT, AND E. J. BALDWIN,

OF SAME PLACE.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 480,656, dated August 9, 1892. Application filed December 1, 1890. Renewed October 5, 1891. Serial No. 407,674. (No model.)

To a/ZZ whom it may @o1/merit:1

Be it known that I, JAMES A. CHRISTY, a citizen of the United States, residing at San Francisco, in the county of San Francisco and 5 State of California, have invented certain new and useful Improvements in Telephones; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others `skilled in the art to IO which it appertains to make and use the same, reference being had to thc accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to improvements in telephones, and has for its object the provision of a simple and effective instrument of this sort having features of novelty in the construction, as will be hereinafter explained,

zo and particularly pointed out in the claim.

The accompanying drawings illustrate what I consider the best means for carrying my invention into practice.

Figure 1 is an elevation of the instrument and so much of the stand as is necessary to understand its application and use. Fig. 2 is a sectional view of the instrument. Fig. 3 is an elevation of the mouth of the instrument with the mouthpiece cut off. Fig. 4 is 3o an elevation of the electrode K removed.

Similar letters of reference indicate corresponding parts in all the figures where they occur.

A is the mouthpiece of the instrument,

3 5 which is cast in one with the side and front walls of the chamber E, as shown in sectional view, Fig. 2.

B is the rear Wall or plate of the chamber, which has a rim or lip b, which projects over 4o the edge of the part B. The parts B and B are united by screws, as shown in dotted lines, Fig. 2, or in any other convenient man- 11012 The instrument is secured to a swinging arm of the stand, as explained and shown in my former application, filed July 12, 1890, Serial No. 358,592, by means of a stud D, screwed over a stud d, formed on or secured in the back of the transmitter. An opening 5c d is formed in stud D for the arm of stand to pass into, and a pinching-screw d2 serves to fasten the stud at any point on the arm.

In the chamber between the parts B and B all the operative parts of the instrument are placed. Over the opening a, leading from the mouthpiece A into the chamber, la wiregauzescreen E is placed for the purpose of breaklng the volume of air passing from the mouth of the person speaking into the airchamber and distributing the air and sound- 6o waves upon the surface of the diaphragm, causing it to vibrate uniformly and not wholly from the center, as if a volume of air nnbroken was passing into the mouth of the receiver-instrument. Said wire-gauze also acts as a shield to protect the diaphragm from injury from any instrument that may be thrust in the mouth of the instrument. Upon this screen lies a rubber washer F, on which is supported the diaphragm G, which may be 7o of any suitable material. A metal washer II rests upon the back of the diaphragm, and a thicker rubber washer I rests upon the washer II, and an insulating-ring J surrounds both Washers H and I and completely insulates them from both of the side walls of the soundchamber.

An electrode' K, formed of metal, hasarino lo resting upon the ring I and has the rea?- plate B of the transmitter resting against 8o the rear face. The electrode K consists of ring or washers k, disposed as above described, the sloping walls or dome K extend forward from the washer in dish-shape, and the disk k2, mounted on the dome and presenting its round face to the diaphragm and in close proximityl thereto. The disk projects beyond the sides of the dome, which latter is provided with aseries of perforaipilirs 7c* 7c* around it beneath the edge of the 9o A metal post L, connected at its forward end to washer II, projects through rubber washer I, through ring or washer 7c, from which it is insulated, and through the back B of transmitter, from which it is also insulated and receives the binding-post M, which carries the battery-Wire, whereby connection is made to the washer H and through it to the diaphragm. The line-wire is connected in any roo suitable manner to the stand, and circuit is through the swinging arm,`stud D, back B', and air-distrbuter K.

K2 is the comminuted material.`

The transmittei as thus constructed constitutes a Very sensitive and eflicient instru ment, from which sounds coming over the Wire are spoken out, so that they can beheard a considerable distance from the instrument with as much distinctness as when held to the ear.

It will be understood that the construction of the instrument herein described can be used as well upon a fixed stationary telephone as upon a movable stand, and I do not confine myself toits application to such a stand.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

ers, and an electrode having a disk in close proximity .to the diaphragm, a perforated dome on which the disk is supported, and a washer in contact with the Walls of the case, as set forth.

` In testimony whereof I affix my signature inv presence of two witnesses.

.JAMES A. CHRISTY.

Witnesses:

H. E. COFFEY, ROBERT MCMILLAN. 

